Allow the player to use the chisel system on tools and clay
This could be done with different items that would act like the chisel and hammer on blocks, however
It would add more variety to the game without changing much of the base mechanics.
It would allow servers that are more casual or roleplay driven to bring themselves really into the world of the game.
It would allow players to show that their creations are beyond just what is "working" matter.
Best of all would be the freedom it allows people to have artistic freedom of not just the land and their character, but the community around them too!